Provided is a protecting device that can prevent damage of the device by releasing the pressure inside the housing by providing openings in the housing and can secure appropriate insulation. The protecting device includes: a meltable conductor 3; first and second external connection terminals 7, 8 connected to both ends of the meltable conductor 3; and a housing 6 having a lower case 4 and an upper case 5, wherein one end of the first external connection terminal 7 and one end of the second external connection terminal 8 are led out from the housing 6, and the housing is provided with a first opening 24 formed facing a front surface of the first external connection terminal 7 and a second opening 25 formed facing a front surface of the second external connection terminal 8.